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-rw-r--r--libblkid/mbsalign.c291
1 files changed, 291 insertions, 0 deletions
diff --git a/libblkid/mbsalign.c b/libblkid/mbsalign.c
new file mode 100644
index 000000000..ea6851f29
--- /dev/null
+++ b/libblkid/mbsalign.c
@@ -0,0 +1,291 @@
+/* Align/Truncate a string in a given screen width
+ Copyright (C) 2009-2010 Free Software Foundation, Inc.
+
+ This program is free software: you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation, either version 3 of the License, or
+ (at your option) any later version.
+
+ This program is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>. */
+
+/* Written by Pádraig Brady. */
+
+#include <config.h>
+
+#include <stdlib.h>
+#include <string.h>
+#include <stdio.h>
+#include <stdbool.h>
+#include <limits.h>
+
+#include "c.h"
+#include "mbsalign.h"
+#include "widechar.h"
+
+
+#ifdef HAVE_WIDECHAR
+/* Replace non printable chars.
+ Note \t and \n etc. are non printable.
+ Return 1 if replacement made, 0 otherwise. */
+
+static bool
+wc_ensure_printable (wchar_t *wchars)
+{
+ bool replaced = false;
+ wchar_t *wc = wchars;
+ while (*wc)
+ {
+ if (!iswprint ((wint_t) *wc))
+ {
+ *wc = 0xFFFD; /* L'\uFFFD' (replacement char) */
+ replaced = true;
+ }
+ wc++;
+ }
+ return replaced;
+}
+
+/* Truncate wchar string to width cells.
+ * Returns number of cells used. */
+
+static size_t
+wc_truncate (wchar_t *wc, size_t width)
+{
+ size_t cells = 0;
+ int next_cells = 0;
+
+ while (*wc)
+ {
+ next_cells = wcwidth (*wc);
+ if (next_cells == -1) /* non printable */
+ {
+ *wc = 0xFFFD; /* L'\uFFFD' (replacement char) */
+ next_cells = 1;
+ }
+ if (cells + next_cells > width)
+ break;
+ cells += next_cells;
+ wc++;
+ }
+ *wc = L'\0';
+ return cells;
+}
+
+/* FIXME: move this function to gnulib as it's missing on:
+ OpenBSD 3.8, IRIX 5.3, Solaris 2.5.1, mingw, BeOS */
+
+static int
+rpl_wcswidth (const wchar_t *s, size_t n)
+{
+ int ret = 0;
+
+ while (n-- > 0 && *s != L'\0')
+ {
+ int nwidth = wcwidth (*s++);
+ if (nwidth == -1) /* non printable */
+ return -1;
+ if (ret > (INT_MAX - nwidth)) /* overflow */
+ return -1;
+ ret += nwidth;
+ }
+
+ return ret;
+}
+#endif
+
+/* Truncate multi-byte string to @width and returns number of
+ * bytes of the new string @str, and in @width returns number
+ * of cells.
+ */
+size_t
+mbs_truncate(char *str, size_t *width)
+{
+ ssize_t bytes = strlen(str);
+#ifdef HAVE_WIDECHAR
+ ssize_t sz = mbstowcs(NULL, str, 0);
+ wchar_t *wcs = NULL;
+
+ if (sz == (ssize_t) -1)
+ goto done;
+
+ wcs = malloc((sz + 1) * sizeof(wchar_t));
+ if (!wcs)
+ goto done;
+
+ if (!mbstowcs(wcs, str, sz))
+ goto done;
+ *width = wc_truncate(wcs, *width);
+ bytes = wcstombs(str, wcs, bytes);
+done:
+ free(wcs);
+#else
+ if (*width < bytes)
+ bytes = *width;
+#endif
+ if (bytes >= 0)
+ str[bytes] = '\0';
+ return bytes;
+}
+
+/* Write N_SPACES space characters to DEST while ensuring
+ nothing is written beyond DEST_END. A terminating NUL
+ is always added to DEST.
+ A pointer to the terminating NUL is returned. */
+
+static char*
+mbs_align_pad (char *dest, const char* dest_end, size_t n_spaces)
+{
+ /* FIXME: Should we pad with "figure space" (\u2007)
+ if non ascii data present? */
+ while (n_spaces-- && (dest < dest_end))
+ *dest++ = ' ';
+ *dest = '\0';
+ return dest;
+}
+
+/* Align a string, SRC, in a field of *WIDTH columns, handling multi-byte
+ characters; write the result into the DEST_SIZE-byte buffer, DEST.
+ ALIGNMENT specifies whether to left- or right-justify or to center.
+ If SRC requires more than *WIDTH columns, truncate it to fit.
+ When centering, the number of trailing spaces may be one less than the
+ number of leading spaces. The FLAGS parameter is unused at present.
+ Return the length in bytes required for the final result, not counting
+ the trailing NUL. A return value of DEST_SIZE or larger means there
+ wasn't enough space. DEST will be NUL terminated in any case.
+ Return (size_t) -1 upon error (invalid multi-byte sequence in SRC,
+ or malloc failure), unless MBA_UNIBYTE_FALLBACK is specified.
+ Update *WIDTH to indicate how many columns were used before padding. */
+
+size_t
+mbsalign (const char *src, char *dest, size_t dest_size,
+ size_t *width, mbs_align_t align, int flags)
+{
+ size_t ret = -1;
+ size_t src_size = strlen (src) + 1;
+ char *newstr = NULL;
+ wchar_t *str_wc = NULL;
+ const char *str_to_print = src;
+ size_t n_cols = src_size - 1;
+ size_t n_used_bytes = n_cols; /* Not including NUL */
+ size_t n_spaces = 0;
+ bool conversion = false;
+ bool wc_enabled = false;
+
+#ifdef HAVE_WIDECHAR
+ /* In multi-byte locales convert to wide characters
+ to allow easy truncation. Also determine number
+ of screen columns used. */
+ if (MB_CUR_MAX > 1)
+ {
+ size_t src_chars = mbstowcs (NULL, src, 0);
+ if (src_chars == (size_t) -1)
+ {
+ if (flags & MBA_UNIBYTE_FALLBACK)
+ goto mbsalign_unibyte;
+ else
+ goto mbsalign_cleanup;
+ }
+ src_chars += 1; /* make space for NUL */
+ str_wc = malloc (src_chars * sizeof (wchar_t));
+ if (str_wc == NULL)
+ {
+ if (flags & MBA_UNIBYTE_FALLBACK)
+ goto mbsalign_unibyte;
+ else
+ goto mbsalign_cleanup;
+ }
+ if (mbstowcs (str_wc, src, src_chars) != 0)
+ {
+ str_wc[src_chars - 1] = L'\0';
+ wc_enabled = true;
+ conversion = wc_ensure_printable (str_wc);
+ n_cols = rpl_wcswidth (str_wc, src_chars);
+ }
+ }
+
+ /* If we transformed or need to truncate the source string
+ then create a modified copy of it. */
+ if (wc_enabled && (conversion || (n_cols > *width)))
+ {
+ if (conversion)
+ {
+ /* May have increased the size by converting
+ \t to \uFFFD for example. */
+ src_size = wcstombs(NULL, str_wc, 0) + 1;
+ }
+ newstr = malloc (src_size);
+ if (newstr == NULL)
+ {
+ if (flags & MBA_UNIBYTE_FALLBACK)
+ goto mbsalign_unibyte;
+ else
+ goto mbsalign_cleanup;
+ }
+ str_to_print = newstr;
+ n_cols = wc_truncate (str_wc, *width);
+ n_used_bytes = wcstombs (newstr, str_wc, src_size);
+ }
+#endif
+
+mbsalign_unibyte:
+
+ if (n_cols > *width) /* Unibyte truncation required. */
+ {
+ n_cols = *width;
+ n_used_bytes = n_cols;
+ }
+
+ if (*width > n_cols) /* Padding required. */
+ n_spaces = *width - n_cols;
+
+ /* indicate to caller how many cells needed (not including padding). */
+ *width = n_cols;
+
+ /* indicate to caller how many bytes needed (not including NUL). */
+ ret = n_used_bytes + (n_spaces * 1);
+
+ /* Write as much NUL terminated output to DEST as possible. */
+ if (dest_size != 0)
+ {
+ char *dest_end = dest + dest_size - 1;
+ size_t start_spaces = n_spaces / 2 + n_spaces % 2;
+ size_t end_spaces = n_spaces / 2;
+
+ switch (align)
+ {
+ case MBS_ALIGN_CENTER:
+ start_spaces = n_spaces / 2 + n_spaces % 2;
+ end_spaces = n_spaces / 2;
+ break;
+ case MBS_ALIGN_LEFT:
+ start_spaces = 0;
+ end_spaces = n_spaces;
+ break;
+ case MBS_ALIGN_RIGHT:
+ start_spaces = n_spaces;
+ end_spaces = 0;
+ break;
+ default:
+ abort();
+ }
+
+ dest = mbs_align_pad (dest, dest_end, start_spaces);
+ size_t space_left = dest_end - dest;
+ //dest = mempcpy (dest, str_to_print, min (n_used_bytes, space_left));
+ memcpy (dest, str_to_print, min (n_used_bytes, space_left));
+ mbs_align_pad (dest, dest_end, end_spaces);
+ }
+
+mbsalign_cleanup:
+
+ free (str_wc);
+ free (newstr);
+
+ return ret;
+}
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